IMPORTANT Adobe Flash Player went out of support on December 31, 2020. For more information, see Adobe Flash end of support on December 31, 2020. Flash content will be blocked from running in Flash Player beginning January 12, 2021. For more information, see Adobe Flash Player EOL General Information Page.
IMPORTANT Windows Server 2012 has reached the end of mainstream support and is now in extended support. Starting in July 2020, there will no longer be optional releases (known as "C" or "D" releases) for this operating system. Operating systems in extended support have only cumulative monthly security updates (known as the "B" or Update Tuesday release).
Improvements and fixes
This security update includes improvements and fixes that were a part of update KB4592468 (released previous December 8, 2020) and addresses the following issues:
- Addresses a security bypass vulnerability that exists in the way the Printer Remote Procedure Call (RPC) binding handles authentication for the remote Winspool interface. For more information, see KB4599464.
- Addresses a security vulnerability issue with HTTPS-based intranet servers. After you install this update, HTTPS-based intranet servers cannot leverage a user proxy to detect updates by default. Scans that use these servers will fail if the clients do not have a configured system proxy.
If you must leverage a user proxy, you must configure the behavior by using the Windows Update policy Allow user proxy to be used as a fallback if detection using system proxy fails. To make sure that the highest levels of security, additionally leverage Windows Server Update Services (WSUS) Transport Layer Security (TLS) certificate pinning on all devices. For more information, see Changes to scans, improved security for Windows devices.
Note This change does not affect customers who use HTTP WSUS servers.
Addresses an issue in which a principal in a trusted Managed Identity for Application (MIT) realm does not obtain a Kerberos Service ticket from Active Directory domain controllers (DCs). This issue occurs after Windows Updates that contains CVE-2020-17049 protections released between November 10 and December 8, 2020 are installed and PerfromTicketSignature is configured to 1 or higher. Ticket acquisition fails with KRB_GENERIC_ERROR if callers submit a PAC-less Ticket Granting Ticket (TGT) as an evidence ticket without providing the USER_NO_AUTH_DATA_REQUIRED flag.
- Security updates to Windows App Platform and Frameworks, Windows Graphics, Windows Media, Windows Fundamentals, Windows Cryptography, Windows Virtualization, and Windows Hybrid Storage Services.
For more information about the resolved security vulnerabilities, please refer to the new Security Update Guide website.
Known issues in this update
|Certain operations, such as rename, that you perform on files or folders that are on a Cluster Shared Volume (CSV) may fail with the error, “STATUS_BAD_IMPERSONATION_LEVEL (0xC00000A5)”. This occurs when you perform the operation on a CSV owner node from a process that doesn’t have administrator privilege.|| |
Do one of the following:
Microsoft is working on a resolution and will provide an update in an upcoming release.
How to get this update
Before installing this update
We strongly recommend that you install the latest servicing stack update (SSU) for your operating system before installing the latest Rollup. SSUs improve the reliability of the update process to mitigate potential issues while installing the Rollup and applying Microsoft security fixes. For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.
Install this update
|Release Channel||Available||Next Step|
|Windows Update and Microsoft Update||Yes||None. This update will be downloaded and installed automatically from Windows Update.|
|Microsoft Update Catalog||Yes||To get the standalone package for this update, go to the Microsoft Update Catalog website.|
|Windows Server Update Services (WSUS)||Yes|| |
This update will automatically sync with WSUS if you configure Products and Classifications as follows:
Product: Windows Server 2012, Windows Embedded 8 StandardClassification: Security Updates
For a list of the files that are provided in this update, download the file information for update 4598278.